chapman



' prii24, 1928. 1,667,586

' v. J. CHAPMAN APPARATUS FOR FUSION WELDING Filed Aug'. 2, 19,26

by y l fHS zqttomy;

W 'M ,4 m

' pr. et, 192s.

'LBIC COMPANY, A lC10'.lltlPQRA'lION OE NEW YORK.

n llipplilcation filed Augiist 2,

My invention relates to fusion' welding and more particularly to a clamping mechanisxrr comprising a backing member of improved construction. Y i

@ In the fusion welding,r of metal parts the 'ledges' to be united are clamped in Juxtaposition upona backing ymember which may ,serve to support the work. With this arrangement, diiculty is frequently encountered due to the factthat the edges do not`lie smoothly upon the backingincinber. If the edges ot the metal parts are not tightly clamped against the backing member, it

is found that a hole will be cut through the 35 metal wherever the metal is not iii good contact' `with the backing member. This is partieularl true with thin metal parts.

An o jectot myinvention'f is to provide an improved arrangement in .which the edges oi." the work Will be tightly clamped at the seam; -A further object of my invention 'is to provide a backing member ot iinproved construction against whichy the parts of tanks and pipes may be clampedduringr i 5 welding in such a manner that the iinish'ed' article will have the coi'i'ectlcurvature at the- Y welded seam.

i It the weldedpipe. or .tank is lto be used as a pressure vessel7 the importance of preserv- S0` ingthe true circular shape of the vessel will be apparent fromthe following considerations. lf thatpart of the vessel near the longitudinal seam is; not truly circular, it will'beforced by the pressure'within the `815 yvessel y'to assume a circular shape. Any changes in pressures within4 the vessel will produce correspondingchanges .in the y'amountnf deformation that takes place at the Seam` and with continuedchanges the 40 continued denture` at the joint will yeventually resultin .failure of the metal in or. at-r the seam. For example, in the process-of manufacturing pipes, pieces of sheet metal areshaped into cylindrical form by passing,r them .through bending rolls before the edges are* united b welding...4 Td'liese rolls', how

ever, d6 not vendto vcircular shape Vthe .first ievv inches andthellast fewyinches `of the v plates that are passed through `them. Cone0 seqnently, 'there are certainrportions'of the` preformed pipes atthe seam that are not truly circular imsection. fclamping means insures-that, these unorme'd pai-tsv will be bentk to `the.correct `curvature"and .APPARATUS non rnsronwnitnme.

ieee. yserial no. 126309.

that while heldin this position welded lso that the finished article will -have a true circular shape at the seam.

My invention will be sidered in connection with the accompany- K better understood' from the following description when con-v ing drawing, and its vscope will be pointed out in the appendedclaims.

.Referring to the drawing, Fig. l shows a front view of a machine in which my invention embodied, Figs. 2, 4 and 5 show sectional views illustrating modifications of my invention, and Fig. 3* shows a variation in thc construction of one of the elements of the invention.l

My invention is of general applicationin the art effusion welding in that it may be used in metallic arc welding, carbon arc Welding4 Where thenrc isbet-ween'the electrode and the work, in gas WeldingI or electric are elding wherein the arc isbetween electrodes ilsed whether the weldingoperation be pered manually or automatically."

{Figi} 1 my invention is shown for the .independently of the Work, 4and it maybe type, examp es of which re now well known in the art. Thismachine comprises pillars 1 and 2 mounted on a ba e 3 arranged to support members 5 and 6, between which tbework is clamped, and a tradk fffor the weldingcarriage 8. This welding carriage is shown as provided with reel 'of Welding wirer9, a meter board 10,. travel motor 11, and a welding head 12. he weldingl head is of suitable construction are by automatically feedingj by it may be advanced*againsty the work' which it clamps between vitselfl andthe holding members 14, `For example, it may be supported' on means adapted to be operated by fluid 'pressurcsfor forcing it into contact with the parts to be welded to clamp these parts to the holding members as setrorth in'v r controlling they .the electrode to maintain the are at substa ti'ally constant' bar'13 em- Letters Patent No. 1,640,437 anted August 30, 1927, on my application, erial No. 9,403, filed February 16, 1925, for electric Weldlng, and assigneto the saine assignee as the present applicatie...

Referring to Fig. 2, which shows in section one construction of my im` `oved backing member together with parts of the coo er' ating work holdingIr members 14 '.aken a ong the section 2 2 ot' Fig. 1, the backing strip 15 against which the work parts are clamped at the seam is illustrated as supported by a second-strip 1G to which it is secured and helr in place by two rods 17 welded to the strip 16. This strip 16, it will bc noted, is of greater breadth than is necessary to support the backing strip 15 and furnishes a support for parts 18 welded thereto which engage the work on each side of the seam and cooperate with holding members 14 which likewise engage the work, but at a point nearer the seam, in such a manner as t0 produce bending moments in the work at the seam and force the edges of the work into intimate Contact with the backing strip 15 and at the same time force the work to assume a circular form at the seam.v

It is apparent that the work-engaging parts 18 ot' the backing member 13 may be separate and distinct from the part that sup- 'ports the backing strip l5 so long as they cooperate with suitable holding members to produce bending moments in the work that will force the edge of the work into intimate contact with` the backing strip and secure the desired bending. In Fig. 2, the parts are made integral and are so arranged relative to the backing strip as to adapt the backing member for work of circular section.

rlhe backing strip 15 may be of any suitable material to which the Weld metal of the joint will not adhere readily. I have found it 'convenient to use a copper strip. The work-engaging surface of this strip l5 is so shaped that it makes contact with the Work along an area oi restricted width to insure thereby a iirin engagement of the work parts with it at the seam as a result of the bending forces set up in the work by the clamp comprising the backing member and the holding members.previously described. The particular eonliguration of the work-engaging surface .oi the hacking strip l5 will vary for different kinds of work. F or thin work, I prefer to construct the strip so as to ailord a narrow \\'orli-cnga'ging portion, while, for heavier work. a wi'der area ol' contact may be provided. For some types of heavy work, it may be desirable to groove the workengngmg portion of this strip that immediately lies beneath the .sc-am, as illustrated in Fig. 3 which shows a section of a` hacking strip suitable for insertion in the backing member shown in Fig. 4, so that thorough penetration may be secured during welding and a reinforcing strip of the 'weld metaly may be farmed on the under side of the work.

The modification shown in Fi ft is similar to that shown in Fig. 2 with t e exception that means are .provided for adjusting the relative location of the parts of the backing bar 13 so that it may be adjusted for work of diil'erent curvatures including flat work. The parts are arranged as in Fig. 2 but provision is made for adjustably ocating the strips 18 relative to the supporting plate 16 and the chill bar or strip i5 `by the provision of screws 19. By loosening the screws 19 and inserting or removing shims between the strips 18and their supporting parts, it is apparent that the curvature determined by the su porting edges of these strips and the centra rid e of the chill bar 15 may be suitably variedl to accommodate work of various curvature. plates the strips 18 are elevated to a level with strip 15. The arrangement illustrated is such that the strips 18 a so servel to clamp the chill bar 15 in place. It is apparent, however, that the construction may assume many forms and that that form illustrated in Fig. 3 is but for the purpose of illustrating the feature of adjustability.

In Fig. 5 I have illustrated a backing member embodying my invention that is particularly adapted for the welding of fiat plates. In the construction illustrated the work-engaging parts 18 of the backing member 13 have been modified to better enable them to coacbwith members 14 in forc- For the accommodation of flat 85 ing the work parts into engagementwith the backing strip 15. In this figure asin the preceding figures the work on each side of" lthe seam is clamped against the baclcin strip by a three-point t antact s stem, one o the lpoints of contact being the acking strip itse The embodiments of the invention illustrated and described herein have been selected for the purpose of clearly setting forth the principles involved. It will be apparent, however, that the invention is susceptible of being modified to meet different conditions encountered in use and I, therefore, aim-to cover by the appended claims all modifications within the true spirit and scope of my invention. Y

lVhat I claim as new, and desire to secure by Letters Patent of the United States, is:

' 1. work clamping mechanism for fusion welding apparatus comprising work holding means arranged along the line of the seam to be welded and spaced laterally therefrom and a backing member comprising a backing' stri havin a relatively narrow workfengaging portion extending along the lilnof the seam and being provided with means for engaging the parts to be welded on eachside of the seam spaced laterally therefrom a. greater distance than said holding means to l Leonesa produce bending moments in the work to lforce' the edges of the parts to be welded into intimate Contact with the. backing str-ip.

2. Work clamping mechanism for fusion welding comprising Work holding members havin edges extending along the line of the seam tween the parts to be welded, a baeking member comprising a relatively narrow edges of the` parts to be welded into intimate ,contact with the backing strip. f

3. Apparatus for fusion welding comprising a backing strip, a support for said backing strip, means spaced laterally from said strip, and means engagingthe ivork between said backing stgip and said spaced means' for clamping th work against the backing strip.- A i 4. Apparatus for fusion welding comprisp ing a backing strip, a support for said .backL Aing strip having Work engaging portions extending laterally beyond said backing strip, and 'means intermediate said backing strip and the work en aging portion of said support coactingwit said portions ot' said support to roducel bending moments in the -Work to orcefthe edges of the Work against said backing strp.and to bend the work parts at the seam. n

5. In a welding machine adapted to weld curved surface curved work parts, work holding members adapted to engage one side of the work parts along the line o the seam to be lwelded at a distance .therefrprm a backing strip having a members, and means for engaging the other ntermediate said holding side of the Work parts on each side of the.,4

seam at a greater distance therefrom than said work holding members.

'- 6L In a welding machine adapted to weld curvedk parts, work clamping mechanism comprising a backing strip, a support for.

said backing strip extendinglaterally beyond saidbacking strip, work supporting members on4 the extending portions of sai support, and means for adjusting said lWorkr supporting ,members relatively to the backing strip to accommodate'work'of varying curvature and means -engaging the work parts between said backing strip and s'aid y work supporting members for clamping the work against said backin strip. Y 7. Work clamping mec anism for fusion welding comprising a backing strip having a I relatively narrow workengaging surface,

means for engaging the Work at a point spaced laterally from the work engaging surface of said backing stripto force the Work against the hacking strip and means for en-r gaging the vvorl on the lsame side of the work as the backing strip and spaced laterally at a greater distance than the first work engaging means whereby a' three-point "0 clamping' effect is produced.

In Witness whereof, I have hereunto set my hand this 30th 'day of July, 1926.

VERNI J. CHAPMAN. y 

